In addition to more elaborate weightlifting equipment comprising or including a plurality of levers, pulleys, weight plates, and various types of mechanical linkages, the traditional weightlifting apparatus has been and still remains a single, straight elongated bar fitted with collars near the ends thereof to retain weighted plates on the bar. A typical free-weight exercising barbell may consist of a pair of substantially equal weights spaced apart near the opposite ends of the bar. The center of gravity of a typical barbell is generally located somewhere along the axis of the gripping bar, usually at the midpoint. The standard straight bar has been widely used for many years for a variety of weightlifting exercises, including, by way of example, military and bench presses, curls, upright and bent-over rows and tricep extensions.
During a typical set for a given exercise, an individual performs a series of repetitions by lifting the barbell between lower and upper positions so that targeted muscles will be stressed. The movement of the gripping hands, depending on the exercise, will generally be along a path having a large vertical component. Some exercises, upright rows for example, require substantially straight up and down motion of the barbell. Other exercises, such as curls, require the hands to move along a somewhat arcuate path having both horizontal and vertical components.
One common exercise done with a free-weight barbell is the curl during which an exerciser may stand with the upper body torso generally aligned vertically. Upon executing curls, the exerciser's gripping hands may move along an arcuate path around the elbow in order to stress the biceps. During one curl repetition, the upper arms will preferably be kept generally aligned with and at the sides of the upper body torso. In the lowered position, the arm is substantially straight, so that the lower arms between the elbows and the hands are also generally aligned with and at the sides of the weight lifter. To raise the barbell from the lowered position, the exerciser bends his arms only at the elbows, while the upper arms generally remain at the exerciser's sides. In the raised position, the lower arms are angled upwardly away from the elbows.
The upright row is an exercise used to develop the upper back, shoulders, and trapezius muscles. During a repetition of this exercise, a weightlifter grips the bar with the palms of the hands facing the user in a standard upright position. The spacing between the user's hands may be varied in order to stress the targeted muscles in different ways. From a lowered position, the user then pulls the barbell upward until the hands are approximately parallel with the shoulders. The barbell is then lowered to the starting position and repeated as desired to complete a set. An exerciser bending approximately 90.degree. at the waist may do bent rows, a variation of the upright row. This variation of the upright row exercise is adapted to target the middle and upper back muscles.
Although standard barbells are useful for exercising targeted muscle groups, the standard barbell exhibits a number of shortcomings. For example, because barbells are unrestricted in movement, and because the weights generally lie along the axis of the barbell, a fatigued user may easily use body momentum, rocking, or bouncing of the weight in order to perform a particular exercise. Accordingly, when a user's muscles tire, or when the weight is too heavy to begin with, the weight lifter may break from proper form and start using jerky or bouncing movement. Such bouncing and jerking movements, when used to complete a repetition will not yield the proper exercise results as compared with proper form and may injure the weightlifter. Another disadvantage of standard barbells is that they do not allow a user to significantly vary angle of grip in order to stress muscles from many different angles.